Includes cardinal parts of plant organs (PO:0025001) as well as parts of other multi-tissue plant structures. Cardinal refers to the fact that these are biologically meaningful and not arbitrary parts. Most cardinal parts of multi-tissue plant structures have both fiat and bona-fide boundaries, including parts with large fiat boundaries, such as leaf base (PO:0020040) or fruit distal end (PO:0008001), and parts with primarily bona-fide boundaries, such as leaflet (PO:0020049).

A plant structure (PO:0009011) that is a proper part of a multi-tissue plant structure (PO:0025496) and includes portions of plant tissues (PO:0009007) of at least two different types.